An organic wastewater adsorbent, a preparation method and application thereof

Abstract

The application discloses an organic wastewater adsorbent and a preparation method and application thereof, and belongs to the technical field of sewage treatment. The preparation method comprises the following steps: subjecting styrene porous microsphere resin to nitration reaction, and then to reduction reaction to obtain amino-modified porous microsphere resin; and through adsorption polymerization, high-nitrogen-content amino organic small molecules and aldehyde small molecules are subjected to polymerization reaction under the action of an alkaline catalyst to generate nitrogen-doped organic porous polymers and coat the surface of the amino-modified porous microsphere resin, so that the organic wastewater adsorbent is obtained. The application utilizes the carrier advantage of the styrene microsphere resin, introduces porous heteroatomic polymers on the microsphere resin to synthesize a kind of porous microsphere resin adsorbent with large adsorption capacity and high organic matter removal rate. When used, the adsorbent is directly added into an organic wastewater solution, and the removal rates of bisphenol A, aniline and tetracycline can all reach more than 90%.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage treatment, and particularly relates to an organic wastewater adsorbent and a preparation method and application thereof. BACKGROUND

[0002] In recent years, the treatment technology of industrial organic wastewater has been continuously developed. Chemical oxidation method is one of the common methods for treating organic wastewater at present. By adding appropriate oxidizing agent to the wastewater, the organic small molecules in the wastewater can be converted into carbon dioxide and water, so that the removal of organic matter is realized. The advantages of this method are low cost and simple operation, but there are also some problems in practical application, such as low treatment efficiency for low-concentration organic wastewater and use of a large amount of chemical agents.

[0003] Resin adsorption method is also a common method for treating industrial wastewater. By introducing specific functional groups on the surface of solid adsorbent, the organic matter in the wastewater can interact with the adsorbent through electron interaction or hydrogen bond, so that the removal of organic matter is realized. This method has the advantages of simple operation and good wastewater purification degree, but the types of resins with large adsorption capacity and high treatment efficiency for organic matter are still few. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the deficiencies and defects mentioned in the above background technology, and to provide an organic wastewater adsorbent with large adsorption capacity and high organic matter removal rate, as well as a preparation method and application thereof.

[0005] To solve the above technical problems, the technical solution provided by the present application is as follows:

[0006] A preparation method of an organic wastewater adsorbent, comprising the following steps:

[0007] (1) nitration reaction of styrene porous microsphere resin to obtain nitro-modified porous microsphere resin;

[0008] (2) reduction reaction of the nitro-modified porous microsphere resin to obtain amino-modified porous microsphere resin;

[0009] (3) polymerization of high nitrogen content amino organic small molecules and aldehyde small molecules under the action of alkaline catalyst to generate nitrogen-doped organic porous polymer and coat the surface of the amino-modified porous microsphere resin, to obtain the organic wastewater adsorbent;

[0010] The high nitrogen content amino organic small molecule is melamine and / or m-phenylenediamine; and the aldehyde small molecule is one or more of glyoxal, 1-aldehyde thiofene and p-phenylenediamine.

[0011] As a further improvement, the nitration reaction in step (1) uses a mixed solution of nitric acid and sulfuric acid.

[0012] As a further improvement, the temperature of the nitration reaction in step (1) is 80-100℃, and the time is 8-12h.

[0013] As a further improvement, the reducing agent used in the reduction reaction in step (2) is one of stannous chloride, sodium borohydride, and lithium aluminum hydride.

[0014] As a further improvement, the temperature of the reduction reaction in step (2) is 40-80℃, and the time is 4-8h.

[0015] As a further improvement, the amount of the high-nitrogen-content amino organic small molecule used in step (3) is 5-10% of the mass of the porous microsphere resin, and the amount of the aldehyde small molecule used is 5-10% of the mass of the porous microsphere resin.

[0016] As a further improvement, the basic catalyst used in step (3) is one of tetrabutylammonium hydroxide, 1-methylimidazole acetate, and sodium hydroxide.

[0017] As a further improvement, the temperature of the polymerization reaction in step (3) is 50-80℃, and the time is 4-8h.

[0018] The application provides an organic wastewater adsorbent prepared by the preparation method.

[0019] The application further provides application of the organic wastewater adsorbent in treatment of organic wastewater.

[0020] Compared with the prior art, the application has the following beneficial effects:

[0021] The application uses styrene-based porous microsphere resin as raw material. Since the styrene-based porous resin itself has fewer heteroatom sites, it cannot well adsorb soluble organic small molecules, so the efficiency of the resin directly used as an adsorbent in treatment of organic wastewater is not high. In order to improve the organic adsorption capacity of the resin, the porous resin is subjected to a nitration reaction to obtain a nitro-modified porous microsphere resin to increase the grafting sites of the resin, and then the nitro-modified microsphere resin is reduced to obtain an amino-modified microsphere resin. The introduction of the amino group not only increases the heteroatom content of the resin but also provides a large number of reaction sites for subsequent polymerization. Finally, high-nitrogen-content amino organic small molecules and aldehyde small molecules are adsorbed and polymerized under the action of a basic catalyst to generate nitrogen-doped organic porous polymers coated on the styrene-based porous microsphere resin, which is the organic wastewater adsorbent.

[0022] Styrene-based porous microspheres resin has high mechanical strength and excellent corrosion resistance, and is a good adsorbent matrix. The introduction of heteroatoms can improve the combination of organic matter and adsorbent. The application utilizes the carrier advantage of styrene-based microspheres resin, introduces porous heteroatom polymer on the microspheres resin to synthesize a kind of porous microspheres resin adsorbent with large adsorption capacity and high organic matter removal rate. When used, the adsorbent is directly added to the organic wastewater solution, and the removal of bisphenol A, aniline and tetracycline can all reach more than 90%. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0024] Figure 1 is the structure diagram of the adsorbent in embodiments 1-2, and the black ball in the diagram represents the resin. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present application, the following will combine the preferred embodiments to make a more comprehensive and detailed description of the present application, but the protection scope of the present application is not limited to the following specific embodiments.

[0026] Unless otherwise defined, all professional terms used in the following have the same meaning as generally understood by those skilled in the art. The professional terms used in this paper are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present application.

[0027] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or can be prepared by existing methods.

[0028] In some specific embodiments, the preparation method of the organic wastewater adsorbent of the present application comprises the following steps:

[0029] (1) Nitration of styrene-based porous microspheres resin to obtain nitro-modified porous microspheres resin.

[0030] In some embodiments, the styrene-based porous microspheres resin can be polystyrene porous microspheres resin, which can be polar or moderately polar, and the particle size is 0.5-5mm. Before use, it is dried at a temperature of 80-120℃.

[0031] In some embodiments, the nitration uses a mixed solution of nitric acid and sulfuric acid, and specifically, nitric acid with a mass fraction of 25-35% and sulfuric acid with a mass fraction of 45-55% are mixed in a volume ratio (3.5-4.5):6 to obtain the mixed solution of nitric acid and sulfuric acid.

[0032] In some embodiments, the nitration temperature is 80-100 DEG C, and the nitration time is 8-12 h.

[0033] (2) The nitro-modified porous microsphere resin is subjected to a reduction reaction to obtain an amino-modified porous microsphere resin.

[0034] In some embodiments, the reducing agent used in the reduction is one of stannous chloride, sodium borohydride and lithium aluminum hydride. The amount of the reducing agent is 5-10% of the mass of the porous microsphere resin. When the reducing agent is stannous chloride, the reduction is performed in a hydrochloric acid solution with a mass concentration of preferably 10%.

[0035] In some embodiments, the reduction temperature is 40-80 DEG C, and the reduction time is 4-8 h.

[0036] (3) The high-nitrogen-content amino organic small molecule and the aldehyde small molecule are subjected to a polymerization reaction under the action of an alkaline catalyst by an adsorption polymerization method to generate a nitrogen-doped organic porous polymer coated styrene porous microsphere resin, i.e., an organic wastewater adsorbent.

[0037] In some embodiments, the high-nitrogen-content amino organic small molecule is melamine and / or m-phenylenediamine. The amount of the high-nitrogen-content amino organic small molecule is 5-10% of the mass of the porous microsphere resin.

[0038] In some embodiments, the aldehyde small molecule is one or more of glyoxal, 1-aldehyde thiofene and p-benzene dialdehyde. The amount of the aldehyde small molecule is 5-10% of the mass of the porous microsphere resin. Compared with formaldehyde, the polymerization reaction of glyoxal, 1-aldehyde thiofene and p-benzene dialdehyde can significantly increase the crosslinking density and significantly improve the adsorption capacity.

[0039] In some embodiments, the alkaline catalyst is one of tetrabutylammonium hydroxide, 1-methylimidazole acetate and sodium hydroxide. The amount of the alkaline catalyst is 0.1-1% of the mass of the porous microsphere resin.

[0040] In some embodiments, the polymerization reaction temperature is 50-80 DEG C, and the polymerization reaction time is 4-8 h.

[0041] The adsorbent of the present application is directly poured into an organic wastewater solution when used. It can be used for removing bisphenol A, aniline, tetracycline and the like in organic wastewater.

[0042] When the adsorption performance of the adsorbent decreases, the adsorbent can be regenerated by reverse washing with ethanol.

[0043] In the following examples, the medium-polar styrene-based porous microsphere resin is D113 macroporous weak acid cation exchange resin from Langfang Senaite Chemical Co., Ltd.

[0044] Example 1

[0045] 1 kg of medium-polar styrene-based porous microsphere resin with a particle size of 2 mm was dried in a 100°C forced air drying oven for 12 h and then used. The dried resin was poured into a mixed solution of 30% nitric acid and 50% sulfuric acid (volume ratio 4:6), and the temperature was raised to 80°C for 10 h of reaction. The nitrated porous microsphere resin was poured into a 10% hydrochloric acid solution, and then 100 g of stannous chloride was slowly added. The temperature was raised to 60°C for 8 h of reaction to obtain the amino-modified porous microsphere resin. 50 g of melamine and 50 g of glyoxal were prepared into an ethanol solution, and the above-mentioned amino-modified porous microsphere resin was poured into the ethanol solution, and then 5 g of tetrabutylammonium hydroxide was added. The temperature was raised to 70°C for 8 h of reaction. After the reaction was completed, the solvent and unreacted raw materials were removed by filtration, and the filter cake was washed with ethanol and then vacuum dried at 80°C for 12 h to obtain the organic wastewater treatment adsorbent.

[0046] Characterization of raw materials, intermediate products, and adsorbents:

[0047] 1. Fourier transform infrared spectroscopy (FTIR):

[0048] After nitration: nitro group (—NO2) characteristic peak (—NO2) appears. ) and . .

[0049] After reduction (amination): the nitro group peak disappears, and the amino (—NH2) stretching vibration peak (—NH2) appears. .

[0050] After polymerization: C=N bond (—C=N) and C-O (—C-O) peaks from aldehyde group polycondensation products, indicating nitrogen-doped polymer coating. . 2. Scanning electron microscopy (SEM) and specific surface area analysis (BET):

[0051] Original resin: smooth surface, small pore size (BET specific surface area < 50 m² / g).

[0052] Prepared adsorbent: surface forms a cross-linked polymer layer, pore size increases (BET specific surface area > 500 m² / g), and pore size distribution is concentrated in 2-5 nm (microporous) and 10-50 nm (mesoporous).

[0053]

[0054] ​​3. Dynamic light scattering (DLS) and thermogravimetric analysis (TGA):

[0055] DLS: The particle size changed from 2 mm (macro-particles) of the original resin to 2-3 mm after coating (no significant change, but the surface roughness increased).

[0056] TGA: The nitrogen-doped polymer coating layer was stable at 300-400 °C with a weight loss rate <10% (the original resin decomposed at 200 °C).

[0057] Take 100 grams of adsorbent and pour it into 1L of a bisphenol A aqueous solution with a concentration of 200 ppm, and place it on a shaker for 1h. After adsorption, test the bisphenol A concentration using a UV spectrophotometer, which is 18 ppm, and the removal rate is 91%.

[0058] Example 2

[0059] Take 1 kg of medium-polarity styrene-based porous microsphere resin with a particle size of 2 mm and place it in a 100 °C air-drying oven for 12h for drying treatment. Pour the dried resin into a mixed solution of 30% nitric acid and 50% sulfuric acid (volume ratio 4:6), and heat to 80 °C for 10h. Pour the nitrated porous microsphere resin into a 10% hydrochloric acid solution, then slowly add 100 grams of stannous chloride, heat to 60 °C for 8h to obtain amino-modified porous microsphere resin. Take 50 grams of melamine and 50 grams of glyoxal to make an ethanol solution, pour the above-mentioned amino-modified porous microsphere resin into the ethanol solution, then add 5 grams of tetrabutylammonium hydroxide, heat to 70 °C for 8h. After the reaction is complete, filter out the solvent and unreacted raw materials, wash the filter cake with ethanol, and then vacuum dry at 80 °C for 12 hours to obtain an organic wastewater treatment adsorbent.

[0060] Take 100 grams of adsorbent and pour it into 1L of aniline wastewater with a concentration of 200 ppm, and place it on a shaker for 1h. After adsorption, test the aniline concentration using a UV spectrophotometer, which is 16 ppm, and the removal rate is 92%.

[0061] Example 3

[0062] Take 1 kg of the medium polarity styrene-based porous microspheres resin with a particle size of 2 mm and dry it in a 100°C blast drying oven for 12 h. Then pour the dried resin into a mixed solution of 30% nitric acid and 50% sulfuric acid (volume ratio 4:6), and heat to 80°C for 10 h. Pour the nitrated porous microspheres resin into a 10% hydrochloric acid solution, then slowly add 100 g of stannous chloride, and heat to 60°C for 8 h to obtain the aminated porous microspheres resin. Take 50 g of melamine and 50 g of terephthaldehyde to prepare an ethanol solution, pour the above-mentioned aminated porous microspheres resin into the ethanol solution, then add 5 g of tetrabutylammonium hydroxide, and heat to 70°C for 8 h. After the reaction is completed, filter to remove the solvent and unreacted raw materials, wash the filter cake with ethanol, and then vacuum dry at 80°C for 12 h to obtain the organic wastewater treatment adsorbent.

[0063] Take 100 g of the adsorbent and pour it into 1 L of a bisphenol A aqueous solution with a concentration of 200 ppm, and place it on a shaker for 1 h. After adsorption, the bisphenol A concentration is tested to be 12 ppm, and the removal rate is 94%.

[0064] Example 4

[0065] Take 1 kg of the medium polarity styrene-based porous microspheres resin with a particle size of 2 mm and dry it in a 100°C blast drying oven for 12 h. Then pour the dried resin into a mixed solution of 30% nitric acid and 50% sulfuric acid (volume ratio 4:6), and heat to 80°C for 10 h. Pour the nitrated porous microspheres resin into a 10% hydrochloric acid solution, then slowly add 100 g of stannous chloride, and heat to 60°C for 8 h to obtain the aminated porous microspheres resin. Take 50 g of melamine and 50 g of terephthaldehyde to prepare an ethanol solution, pour the above-mentioned aminated porous microspheres resin into the ethanol solution, then add 5 g of tetrabutylammonium hydroxide, and heat to 70°C for 8 h. After the reaction is completed, filter to remove the solvent and unreacted raw materials, wash the filter cake with ethanol, and then vacuum dry at 80°C for 12 h to obtain the organic wastewater treatment adsorbent.

[0066] Take 100 g of the adsorbent and pour it into 1 L of an aniline aqueous solution with a concentration of 200 ppm, and place it on a shaker for 1 h. After adsorption, the aniline concentration is tested to be 20 ppm, and the removal rate is 90%.

[0067] Example 5

[0068] Take 1 kg of medium polarity styrene-based porous microspheres resin with a particle size of 2 mm and dry it in a 100°C blast drying oven for 12 h. Pour the dried resin into a mixed solution of 30% nitric acid and 50% sulfuric acid (volume ratio 4:6), and heat to 80°C for 10 h. Pour the nitrated porous microspheres resin into a 10% hydrochloric acid solution, then slowly add 100 g of stannous chloride, and heat to 60°C for 8 h to obtain the aminated porous microspheres resin. Take 50 g of m-phenylenediamine and 50 g of p-phenylenedialdehyde to prepare an ethanol solution, pour the above-mentioned aminated porous microspheres resin into the ethanol solution, then add 5 g of tetrabutylammonium hydroxide, and heat to 70°C for 8 h. After the reaction is completed, filter to remove the solvent and unreacted raw materials, wash the filter cake with ethanol, and then vacuum dry at 80°C for 12 h to obtain the organic wastewater treatment adsorbent.

[0069] Take 100 g of the adsorbent and pour it into 1 L of a tetracycline aqueous solution with a concentration of 200 ppm, and place it on a shaker for 1 h. After adsorption, the tetracycline concentration is tested to be 16 ppm, and the removal rate is 92%.

[0070] Comparative Example 1

[0071] Take 1 kg of medium polarity styrene-based porous microspheres resin with a particle size of 2 mm and dry it in a 100°C blast drying oven for 12 h. Pour the dried resin into a mixed solution of 30% nitric acid and 50% sulfuric acid (volume ratio 4:6), and heat to 80°C for 10 h. Pour the nitrated porous microspheres resin into a 10% hydrochloric acid solution, then slowly add 100 g of stannous chloride, and heat to 60°C for 8 h to obtain the aminated porous microspheres resin. The aminated resin is not coated with a polymer and is directly used for adsorption experiments.

[0072] Take 100 g of the aminated resin and pour it into 1 L of a bisphenol A aqueous solution with a concentration of 200 ppm, and place it on a shaker for 1 h. After adsorption, the bisphenol A concentration is tested to be 82 ppm, and the removal rate is 59%.

[0073] Comparative Example 2

[0074] 1kg of the medium-polar styrene-based porous microsphere resin with a particle size of 2mm was placed in a 100°C blast drying oven for 12h for drying treatment, and the dried resin was poured into a mixed solution of 30% nitric acid and 50% sulfuric acid (volume ratio 4:6), and was heated to 80°C for 10h. The nitrated porous microsphere resin was poured into a 10% hydrochloric acid solution, and then 100g of stannous chloride was slowly added, and the mixture was heated to 60°C for 8h to obtain the amino-modified porous microsphere resin. 50g of melamine and 50g of formaldehyde were prepared into an ethanol solution, the above-mentioned amino-modified porous microsphere resin was poured into the ethanol solution, and then 5g of tetrabutylammonium hydroxide was added, and the mixture was heated to 70°C for 8h. After the reaction was completed, the solvent and unreacted raw materials were removed by filtration, and the filter cake was washed with ethanol and then vacuum dried at 80°C for 12h to obtain the adsorbent.

[0075] 100g of the adsorbent was poured into 1L of a bisphenol A aqueous solution with a concentration of 200ppm, and was placed on a shaker for 1h for adsorption. After adsorption, the bisphenol A concentration was tested to be 64ppm, and the removal rate was 68%.

[0076] Comparative Example 3

[0077] 1kg of the medium-polar styrene-based porous microsphere resin with a particle size of 2mm was placed in a 100°C blast drying oven for 12h for drying treatment, and the dried resin was poured into a mixed solution of 30% nitric acid and 50% sulfuric acid (volume ratio 4:6), and was heated to 80°C for 10h. The nitrated porous microsphere resin was poured into a 10% hydrochloric acid solution, and then 100g of stannous chloride was slowly added, and the mixture was heated to 60°C for 8h to obtain the amino-modified porous microsphere resin. 50g of melamine and 50g of formaldehyde were prepared into an ethanol solution, the above-mentioned amino-modified porous microsphere resin was poured into the ethanol solution, and then 5g of tetrabutylammonium hydroxide was added, and the mixture was heated to 70°C for 8h. After the reaction was completed, the solvent and unreacted raw materials were removed by filtration, and the filter cake was washed with ethanol and then vacuum dried at 80°C for 12h to obtain the adsorbent.

[0078] 100g of the adsorbent was poured into 1L of a bisphenol A aqueous solution with a concentration of 200ppm, and was placed on a shaker for 1h for adsorption. After adsorption, the bisphenol A concentration was tested to be 64ppm, and the removal rate was 68%.

[0079] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present application, without departing from the technical solution of the present application, shall fall within the scope of protection of the technical solution of the present application.

Claims

1. A method for preparing an organic wastewater adsorbent, characterized by, The method comprises the following steps: (1) nitration of styrene-based porous microspheres to obtain nitro-modified porous microspheres; (2) reduction of the nitro-modified porous microspheres to obtain amino-modified porous microspheres; (3) polymerization of high-nitrogen-content amino organic small molecules and aldehyde small molecules under the action of an alkaline catalyst to obtain nitrogen-doped organic porous polymers and coat the surface of the amino-modified porous microspheres, thereby obtaining the organic wastewater adsorbent. The high-nitrogen-content amino organic small molecules are melamine and / or m-phenylenediamine; and the aldehyde small molecules are one or more of glyoxal, 1-aldehyde thiofene, and p-phenylenediamine.

2. The method for preparing an organic wastewater adsorbent according to claim 1, characterized by, The nitration reaction in step (1) uses a mixed solution of nitric acid and sulfuric acid.

3. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The nitration reaction in step (1) is performed at a temperature of 80-100℃ for 8-12h.

4. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The reducing agent used in the reduction reaction in step (2) is one of stannous chloride, sodium borohydride, and lithium aluminum hydride.

5. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The reduction reaction in step (2) is performed at a temperature of 40-80℃ for 4-8h.

6. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The high-nitrogen-content amino organic small molecules in step (3) are used in an amount of 5-10% of the mass of the porous microspheres, and the aldehyde small molecules are used in an amount of 5-10% of the mass of the porous microspheres.

7. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The alkaline catalyst in step (3) is one of tetrabutylammonium hydroxide, 1-methylimidazole acetate, and sodium hydroxide.

8. The method for preparing an organic wastewater adsorbent according to claim 1, wherein: The polymerization reaction in step (3) is performed at a temperature of 50-80℃ for 4-8h.

9. An organic wastewater adsorbent, characterized by, The organic wastewater adsorbent is prepared by the preparation method of any one of claims 1-8.

10. Use of the organic wastewater adsorbent of claim 9 in the treatment of organic wastewater.

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